/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.channel;

import io.netty.util.concurrent.OrderedEventExecutor;

/**
 * Will handle all the I/O operations for a {@link Channel} once registered.
 *
 * One {@link EventLoop} instance will usually handle more than one {@link Channel} but this may depend on
 * implementation details and internals.
 *
 */
public interface EventLoop extends OrderedEventExecutor, EventLoopGroup {

    @Override
    default EventLoop next() {
        return this;
    }

    /**
     * Returns an <em>internal-use-only</em> object that provides unsafe operations.
     */
    Unsafe unsafe();

    /**
     * <em>Unsafe</em> operations that should <em>never</em> be called from user-code. These methods
     * are only provided to implement the actual transport, and must be invoked from the {@link EventLoop} itself.
     */
    interface Unsafe {
        /**
         * Register the {@link Channel} to the {@link EventLoop}.
         */
        void register(Channel channel) throws Exception;

        /**
         * Deregister the {@link Channel} from the {@link EventLoop}.
         */
        void deregister(Channel channel) throws Exception;
    }
}
